Celtic may face a heated encounter with Linfield in the second qualifying round of the Champions League, while RB Salzburg could yet force UEFA to exclude sister club RB Leipzig from the tournament.
Brendan Rodgers' Celtic, a club known for strong Catholic affiliations, were drawn against either La Fiorita of San Marino or Northern Ireland's Linfield, a Belfast side with prominent Protestant connections.
A further complication for the clubs, UEFA and local police is the potential date of the first leg, should Linfield progress. The opening matches of each tie are due to be played on July 11 or 12, the latter of which often sees marches conducted by the Ulster Protestant Orange Order.
Having been drawn against Hibernians FC of Malta or Estonia's FCI Tallinn, Salzburg could also cause UEFA a headache.
The governing body's statutes prevent owners from controlling more than one club per season in its competitions, with the higher ranked side in such a situation being given preference.
That would mean the Austrian champions could retain a place in the group stage, should they advance that far, at the expense of RB Leipzig, the Bundesliga's surprise runners-up.
UEFA were last month quoted as saying: "All criteria, including matters of ownership, will be verified for each club by UEFA only once we have received the competition entry forms and documentation from the national football associations and clubs, following the end of the season in the respective leagues".
Champions League second qualifying round draw in full:
APOEL v Dudelange
Zalgiris v Ludogorets Razgrad
Qarabag v Samtredia
Partizan v Buducnost Podgorica
Hibernians/FCI Tallinn v Salzburg
Sheriff Tiraspol v Kukes
Astana v Spartaks Jurmala
BATE Borisov v Alashkert/FC Santa Coloma
Zilina v Kobenhavn
Hapoel Beer-Sheva v Honved
Rijeka v The New Saints/Europa
Malmo v Vardar
Zrinjski v Maribor
Dundalk v Rosenborg
FH Hafnarfjordur v Vikingur/Trepça '89
Linfield/La Fiorita v Celtic
IFK Mariehamn v Legia Warszawa